Air-compressor.



1. B. KENDf-ILL. AIR COMPRESSOR.

APPLICATION FILED SEPT-11. 191!- 1,299,478, Patented Apr. 8,1919.

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J. B. KENDALL.

AIR COMPRESSOR.

APPLICATION FILED sEyT. 11. 1'91 1.

Patented Apr. 8, 1919.

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. 5M Q NM WI TNESSES l. B. KENDALL.

AIR COMPRESSOR. APPLICATION man SEPT-17.!9H.

Patented Apr. 8,1919;

LNVENTOR.

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JjMEs BYMM ATTORNEYS 1. B, KENDALL. AIR COMPRESSOR. APPLICATION FILED SEPT- 17. [91]- Patented Apr. 8,1919. I

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JAMES B. KENDALL, CHICAGO, ILLINOIS,

ASSIGNOR- TO NEWSTARTEB MANUFAC- TUBING COMPANY, OFOHICAGO, ILLINOIS, A. CORPORATION O15" ILLINOIS.

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Specification of Letters Patent.

Patented Apr. 8, 1919.

Application filed September 17, 1917. Serial No. 191,812.

To all whom it may concern:

Be it known that I, JAMES B. KENDALL, a' citizen of the United States, and a resident of the city of Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Air- Compressors; and I do hereby declare that the following description of my said invention, taken in connection with the accompanying sheet of drawing, forms a full, clear, and exact specfication, which will enable others skilled in the art to which it appertains to make and use the same.

My invention relates generally to im provements in air compressors; and it consists, essentially, in the novel and peculiar combination of parts and details of construction, as hereinafter first fully set forth and described and then pointed out in the claims.

The object of this invention is the production of an efficient, and serviceable air compressor, which, while adapted for general use,

is more particularly designed for compressing air in self-starting devices for internal combustion engines, and which is especially well adapted for use in automobiles and motor trucks, and particularly, for that class of Ford cars, so called, which are not provided with self-starting means, but must be cranked to initiate the running of the motor.

This air compressor is of the two-stage, opposed cylinders type of machines; it is very compact, and can be sold at such a reasonable figure as to be an inducement to owners of motor vehicles not supplied with self-starters, to install this system in their cars.

In the drawings, forming a part of this specification, and which illustrate the preferred embodiment of my invention, Figure 1 is a longitudinal vertical sectional view of this air compressor, drawn on line 11 of' Fig. 2. Fig. 2 is a longitudinal horizontal section of the same on line 2-2 of Fig. 1. Fig. 3 is an end elevation of the machine. Fig. 4 is a detached front elevation of the cylinder head applied to the first-stage, or large compression cylinder. Fig. 5 is a sectional view of the same on line 55 of Fig. 4. Fig. 6 is an end view of the same. Fig. 7 is a plan of the cylinder casting detached. Fig. 8 is a front elevation of the same. Fig. 9 is an end view of the smaller the larger cylinder end. Fig. 11 is a side view of the twin pistons detached. Fig. 12 is a plan of a portion of the same; and Fig. 13, is a sectional view on line 13-13 of Fig. 12. Fig. 14 is a longitudinal sectional view of the wrist-pin detached; and Fig. 15 is a transverse sectional view of the same, on line 15'15 of Fig. 1a. Fig. 16 is a plan View of the cut-out mechanism ofthe machine. Fig. 17 is a side view of the same, partly in section. Fig. 18 is an inverted plan thereof; and Fig. 19 is a'sectional view on line 1919 of Fig. 17. Fig. 20 is an elevation of the wabbling disk employed in this device; and Fig. 21 is a sectional view of the same. Fig. 22 is a sectional view on line 2222 of Fig. 23, of the clutch and driver sprocket wheel by which the compressor is started and stopped. Fig. 23 is an end elevation of the same. Fig. 24 is a sectional view of a fragment of the device illustrated in Figs. 16, 17, and 18, and

showing the diaphragm by which the stopcylinder end, and Fig. 10 is alike view of cut away to disclose underlying elements.

Fig. 26 is a plan of the latch employed in this device. Fig. 27 is an end elevation of the rightend thereof, and Fig. 28 is a sectional view of the same on line 28 of Fig. 26. Fig. 29 is an elevation on an increased scale, of a portion of the cylinder head of the second stage compression cylinder. Fig. 30 is a sectional view of the same on line 30-30 of Fig. 29. Fig. 31 is an inverted plan, and Fig. 32 is-v an edge view of the same. Fig. 33.is an end elevation of thecompressor, illustrating its connection with the motor of a Ford car, the motor being illustrated rather diagrammatically and without refer ence to details of construction except such as are necessary to show this connection.

Like parts are designated by the same characters and symbols of reference in all the various figures.

The principal part of this machine comprises a casting having at one end the large, or first-stage compression cylinder A, and at its other end the smaller, or second stage compression cylinder B, both cylinders being axially 'alined and separated by a chamber C, in which portions of the operating mechanism are located. In these cylinders there is movably located a twin piston,

comprising a central, cylindrical, portion 33, which is connected by oppositely extending, alined bars 35, one of which terminates in the smaller piston 36, and the other of which ends reduced portions which are externally screw threaded to receive flanged nuts 42, so that when the wrist-pin has been inserted in the bore 39 of the cylindrical portion 34, the flanged nuts 42 will bear against the opposing faces of the cylindrical portion 33, and thereby securely retain the wristpin in position.

In the opposing side walls 43, 44, of the central chamber 0, there are axially alined bearings 45,46, and in these bearings there is rotatably mounted a. shaft 47, which I shall hereafter term the operating shaft, and which is best shown in Figs. 1, and 21. This operating shaft has its two ends screwthreaded to receive nuts 48, 49; and adjacent the locking nut 49 there is placed a sleeve 50, which sleeve has one end externally screw-threaded, as at 51, and upon this screw-threaded portion 51, there .is placed a driven sprocket wheel 52. Upon the shaft 47- there is secured an annular body 53, which will be hereinafter called the wabbling disk. This wabbling disk has a cylindrical bore 54, to receive the operating shaft 47, and to which it is, preferably, fastened by a set screw 55. This bore 54 is inelined to the axial line of the body of the wabbling disk 53, whereby said wabbling disk receivesits throw. This cylindrical body- 53 has on its periphery an annular flange 56, by which it is rotatably retained in a cylindrical .casing 57, which is bored as at 58, to receive one end of the wabbling disk 53; and this bore is then enlarged, as

at 59, to permit the laterally extending flange 56 to enter said enlarged bore. This latter'bore is internally screw-threaded to receive a follower 60, which follower is an annular ring the bore of which receives the outer end 61,of the crank 53, while its inner flank bears an antifriction ring 62; there being a like antifriction ring 63, interposed between said flange 56, and the bottom of the enlarged bore, to reduce friction as far as possible. In theouter flank of the follower 60 there are a series of notches or grooves 64, which serve primarily as means for applying a spanner wrench to screw the follower into the casing 57, and. then as a means to receive a wlre loop .65, passed through a hole in the casing and entering one of said notches 64, as clearly illustrated in Figs. 20 and 21, to lock said follower to said casing 57.

On the casing 57, andradially extending therefrom, there is a pin 66, which pin, when the wabbling disk is mounted in the chamber C, and the twin piston'in positlon in the cylinders, engages the transverse hole 46 in the wrist-pin 40, to operate the istons, as will hereinafter appear; and tl dis pin also passes through the oblong apertures 38 in the central portion 33 of the twin pistons to reach the wrist-pin, and at the same time prevent the rotation of said twin pistons.

The operating shaft 47 with its wabbling disk 53, and the casing 57 surrounding the same, are located in the chamber C, which, as shown in Fig. 8, has an open front through which the wabbling disk and its caslng are introduced to the chamber C, which front is closed by a plate 152, Fig. 3, fastened to the chamber C, by screws 153. By this construction the chamber C serves as an oil-reservoir to lubricate the parts in sand chamber which lubrication is attained by the rapid rotation of the parts therein splashing the lubricant all over the casing and reaching also the two c linders A, B. The larger cylinder A is c osed by a cyllnder head D, shown in detail in Figs. 3, 4, 5, and 6. This cylinder head is of oblong contpur, as is also the flange 67 on the large cylinder; and on this cylinder head D there is ntegrally formed a tubular boss 68, which has in its bore a ball, or other suitable valve 69, Fig. 2, retained upon its seat by a coil spring 70, the upper end of this bore 71, being internally screw-threaded and closed by a plug 72. The valve 69 normally closes a large cylinder leads an outlet cylinder head D and surrounding this hole there are a series of intake holes 76. The central hole 75 has, in a recess in the back of the cylinder head, a valve seat 7 5?, Fig. 5, upon which seats a valve 77, Fig. 2, the stemof which asses A, and from the bore 71 passage 74. Through the passage 73, leading to thethere is drilled a hole 75; i

through the central hole 75 and exten s beyond the face of the cylinder head D for.

some distance, and terminates in a fixed washer 78. A spiral spring 79 surrounds this stem 'of valve 77, and functions to keep' through a hole 90, there being on said valve stem a spiral spring 91, Fig. 2, which normally forces the valve 86 against its seat, the end of the bore 82 being closed by a plug 92. From the boss 81 extends a tubular boss 93, the bore of which is closed by a plug 94, Fig. 30, engaging the internally screw-threaded bore 95. This bore is in open' communication with the bore 82 of the boss 81, and it has a side outlet 95*, the object of which will now be described.

At the back of the cylinder casting A, B, C, there is integrally formed a rib or projection 96, through. which is drilled a passage 97, which reaches from the face of the large cylinder to the face of the small cylinder, and the side outlet 95, in the cylinder head E connects with this passage 97 at one end, while the passage 73 in the cylinder head D, (Fig. 5) connects with said passage 97 at the other end. By these passages 74, 97, and 95, av direct communication between the cylinders A, B, is established past the cylinders and the central chamber C.

Again referring to the-cylinder head E, there is formed at the back of the plate 80, a rib 98, which terminates in a, preferably rectangular, plate 99, standing at right angles to the plate 80; and through this boss or rib 98, and'connecting with the boss 81,

there is drilled a passage 100, which outlets in the face of the plate 99, as clearly illustrated in Figs. 29 and 31. To this plate 99 there is screwed,by screws 101,Fig. 1, an element F, Fig. 3, which I term the cut-out, detailed in Figs. 16 to 19 inclusive, and also in Figs. 24 and 25. This cut-out comprises a plate 102, which has screw holes for the reception of the before-mentioned screws 101. In the face of this plate 102 there is a circular depression or recess 103, and a smaller recess 104, and finally an opening 105 through the remainder of the plate 102. Connected to plate 102 is a bar 106, which terminates in a tubular boss 107, the bore of which is closed by a plug 108, Fig. 19. This tubular boss 107 connects witha second tubular boss 109, placed at right angles to the boss 107, the lower endof which boss 109 is transversely slotted asat 110, Figs. 18 and 19. From the lower face 'of the plate 102 extend two lugs 111, which are punctured for the passage of a' bolt 112, upon which there'is pivoted a'ba'r 113, which will be hereinafter calledthe latch. This latch has near one end an adjusting screw 114. ch-

tering the hole 105 in the plate 102, which Y adjusting screw 114 is prevented from acci dental rotation by a set screw 115. In the again referred to.

bore of the boss 107 there is located a coil spring 116, Figs. 18 and 19, which spring acts on the latch 113 to depress the same.

In the recess 103 in the plate 102 there is located a metallic diaphragm 117, Figs. 24

placed'in the recess 104 a disk, which may be termed a follower, against which the adjusting screw 114 contacts, while the follower 118 bears against the under side of the diaphragm 117. Intcrposed between the diaphragm and the plate 99 and the plate 102, there are packin washers 119, to prevent air from escaping etween the joints of these parts.

Referring to Figs. 7, 8, 9, and 10, there extends from the,back of the cylinders A, B, two bars 120, 121, which bars are punctured at their ends as at 122, in which there is located a screw-bolt 123, to be hereinafter From the back of the chamber C extends a punctured lug 124, through which, and the bore of the boss 109 on the cut-out F, Fig. 17, thereis passed a bar 125, at one end of which there is pivotally connected an operating lever 126, which, with its lower extremity bears against an abutment 127, Figs. 1,17, and 19, formed on the boss 109 of the cut-out F, the other end and 25; and below this diaphragm there is is formed a cylindrical shank 131. On this shank there is rotatably mounted a driving sprocket wheel 132. In the hub of this sprocket wheel there are'two, diametrically opposite holes; and'in the face of the socket 130 there are two corresponding recesses 133, Fig. 22.

In front of the sprocket wheel 132there is placed a disk 134, on which there is centrally formed a shank 135, and on this shank there is mounted a washer 136, spaced from the disk 134 to admit the fork 128 on the rod 125 between them. To this disk 134 are affixed two pins 137, which pass through the hub of the driving sprocket 132, and normally enter the recesses 133 in the socket 130. When thus engaged, the socket 130 when r0- tating, communicates rotativef' movement to the sprocket wheel by said pins, but when said rod 125 is free to move longitudinally in the direction shown by an arrow in Fig. 22, by a spring 138, surrounding said rod 125, the disk will draw the pins 137 out of the recesses 133 and thereby disconnect the sprocket wheel from its driving element. Bypulling the lever 126 in the direction indicatedby an arrow in Fig. 1, the clutch disk 134 with its pins 137 may be moved to reestablish the connection between the drivlng element and the driving sprocket wheel. In

order to hold this sprocket wheel in engaged position, there is formed, on the rod 125, a notch 139, Fig. 17, wherewith a notch 140, Fig. 26, in the latch 113 engages to hold the 'rod 125 in clutch-engaging position. Tore-,, lease this rod 125, and to disengage the clutch from the driving element 129, I employ the automatically operating device comprising the diaphragm and correlated parts as hereinbefore described.

The driving sprocket 132 is connected to the driven sprocket 52, on the crank shaft, by a link belt 141, as clearly shown in Fig. 33.

The operation of this air compressor, is essentially, as follows:

The driving sprocket 132 rotates the driven s rocket, 52, mounted on the operating sha t 47, and this shaft rotates the wabbling disk 53, which, in turn, reciprocates the pin 66 on the casing 57 which surrounds the crank.- This reciprocating movement is communicated to the twin pistons by the wrist-pin 40, with. which the pin 66, entering the transverse hole 41 in 'sald wrist pin, is connected. Air is drawn into the large cylinder A, through the opening of the valve 77, which air, on the return stroke of the pistons is compressed and expelled from the cylinder A by closing the valve 77 and opening the valve 69. This air, having .received its first stage of comression, now passes through-the passage 73 in the cylinder head D, and the passages ,97 and 95*, into the bore 82 and opening the valve 88, into the smaller cylinder B, from whence the air, in its second stage of compression, escapes,'or is forced, by opening the valve 85, on the return stroke of the smaller piston to pass through the nipple 87 to a storage tank, not shown. There is in the exit assage 83 in the boss 81 of the cylinder ead E, the small passage 100, which leads to the upper surface of the diaphra 117; and as the air in the cylinder B is eing compressed, this diaphragm will be downwardly depressed, moving with it the follower 118, which, acting through the adjusting screw 114 upon one end of the latch 113 and depressing the same, causes the other end thereof to rise and gradually move the latch 113 out-of the notch 139 in the rod 125, so that, when the predetermined compression ,of air has been attained, the

latch 113 will have released the rod 125,

p the spring 138 thereon will move the rod 125 longitudinally, and thereby disconnect the driving sprocket from the driving element, and thus stop the compressor. It may now be noted that this stopping of "the compressor is entirely automatic, as'soon as the predetermined air compression has been reached, the degree'of which can be regulated by the. adjusting screw 114. This stopping cannot be controlled by the lever 126, which can only function to start the compressor, when desired, or when thepressure in the storage tank falls below ,the ;predetermined pressure, by manipulating the lever 126. Instead of connecting this automatically and manually operating means for starting and stopping the air compressor'to the dr-iving sprocket 132, I may provide the driven sprocket 52, on the operating shaft 47' with the clutch mechanism shown inFigs. 2, 22, and 23, in connection with the driving sprocket 132, and connect the rod 125 with its fork 128, to the driven sprocket, a change which would be a reversal of the order of arrangement, and as such, clearly within the. scope of my invention. This change would probably be desirable in a case-where the air compressor is more or less remotely located from the prime mover.

In the preamble to this specification I have stated that this air compressor is especially well adapted for use in a Ford car; and in Fig. 33 I have indicated how this air compressor can be connected to the motor of .this, or any other car having the same, or a similar engine. This engine has a link 145, having at each end an eye, which link, at one end, engages the bolt 123 in the two rearwardly extending bars 120, 121, extending-from the air compressor,the other end of said link engaging an element 146, on the motor casing through which the motor shaft to which the clutch mechanism is secured, is passed, thereby securing the air compressor to the motor M and affording one of the two connections of the air compressor to the motor M. On the back of the central portion of the cylinder casting there is formed a boss 142, which is tapped to receive 'a screw-eye 143, which engages a bolt 144 found on the motor M, thus forming a second, and adjustable, connection with the motor. This screw-eye 143 performs the additional function of serving as a means for taking up slack in the linkbelt 141, by unscrewing the screw-eye more or. less, as the condition of the link belt may require. And it may here be stated that the bolt 123 serves as a pivot on which the air compressor may swing to permit of the adjustment of the link belt being made.

..In order to take up wear or slack in the operating shaft 47 there areprovided in the end of one or both of the adjusting nuts 48, 49, a series of notches 1.50, Fig. 3, wherewith the pin 151, passing through the shaft 47, may engage. By wlthdrawing this in and rotating the nut, wear may be ta en up,

and then the nut again secured against rotation, by inserting the pin to engage the nearest notch into which it Will fit. And instead of a pin, or pins, I may use wire loops, such as are shown at 65, in Fig. 21, for this purpose. By means of the lateral movement of the operating shaft 47, I am, furthermore, enabled to so adjust the twin pistons that neither of said pistons can strike the respective cylinder head, said pistons being so constructed that there is, for well-known reasons, but a very limited clear ance between the ends of the pistons and the cylinder heads! Thus, longitudinally moving the operating shaft, causes a corresponding movement of the twin piston, so that their proper location can, at all times, be

maintained. This is a very important fea' ture of my invention which positively avoids any knocking of the pistons against one or the other of the cylinder heads.

This machine operates perfectly noiseless and without jar, jolt, or knocking, so that it is especially well adapted for use in automobiles.

I have hereinbefor described with considerable minuteness the preferred embodiment of my invention, but I desire it to be understood that I am aware the details of construction disclosed, may be varied, and parts omitted without departing from the scope of my invention as defined in the subjoined claims.

Having thus fully described this invention, I claim as new, and desire to secure to myself by Letters Patent of the United States 1. The combination, with a motor, of an air compressor, said air compressor having two means for connecting the same to said motor, viz. a pivotal connection, and an adjustable connection, said connections comprising two bars and a boss projecting rearwardly from the air compressor, a' bolt mounted in said bars, a link mounted at one end to said bolt and at the other end to an element on said motor to afford a pivoted connection between said. air compressor and the motor, there being in screw-threaded connection with said boss a screw-eye, sai screw-eye engaging a screw-bolt on said motor to afford adjustable means for connecting said air compressor to the motor for taking up slack in the connection between the driving element of the motor and the driven element of the air compressor, said motor having a driving element, and said air compressor having a driven element operatively connected to said drivin element, manually operated means for initiating the operation of said air compressor, and automatically operated means for stopping the air compressor when a predetermined air compression has been attained.

2. In an air compressor, the combination,

that many of including a substantially rectangular, boxlike casing, said casing having at its upper end oppositely extending cylinders, said cylinders having difi'ering bores, said cylinders being in axial alinement, an air conduit formed integrally with said cylinders and said casing and extending from the outer end of one cylinder to the outer end of the other cylinder, a twin piston in said cylinders, means for operating said pistons, a cylinder head at the outer end of .one of the cylinders, said cylinder head having an inlet valve to admit air to said cylinder, said cylinder head having a tubular boss, a passage in said boss connecting said cylinder to one end of the aforesaid air con-.

duit, a valve in said passage normally clos- 111g said passage, a second cylinder head at the outer end of said second cylinder, said second cylinder head having two tubular bosses, a branch leadin from one end of said bosses, said branchfiiaving a bore connecting at one end with the other 'end of said air conduit and its .other end withone of said tubular bosses, an inlet valve in the bore of the latter tubular boss permitting the admission of air from the first-named cylinder, an air valve in the second of said tubular bosses, a discharge nozzle leading from the second tubular boss, a downwardly extending tubular rib leading from the latter tubular boss, a flange in which the said tubular rib terminates, a second flange bolted to the first-named flange, a diaphragm interposed between these two flanges, and mechanism operable by the distention of said diaphragm for arresting the means for operating said twin piston.

3. Inyan air compressor, a casing, comprising a substantially rectangular casting, said casing being open at one side, said open side being closed by a cover bolted thereto,

there being projecting from the flanks of said casing at the upper end thereof apair of cylinders, said cylindersbeing in axial said bosses being constructed to afford bearings for an operating shaft traversing said casing.

4. In an a1r compressor, a caslng, comprising a substantially rectangular casting,

said casing being open at one side, said open side being closed by a cover bolted thereto,

operating mechanism to be inserted into said casing through said opening, there being projecting from the flanks of said casing at the upper end thereof a pair of cylinders, said cylinders being in axial alinement, said cylinders being formed integrally with said casing, said cylinders being open at their inner and their outer ends, there being on said cylinders a rib integral withsaid cylinders and extending from the outer ends of said cylinders to said casing, a continuation of said rib being formed integrally with the upper end of said casing, there being in said rib a bore extending from the outer end of one cylinder to the outer end of the 0pposing cylinder, there being projecting from the flanks of said casing at the lower end thereof tubular bosses, said bosses being in axial alinement and in parallel relationship to the axial line of said cylinders said bosses being constructed to afford bearings for an operating shaft traversing said casing, there being projecting from the upper rear end of said casing two spaced apart bars, said bars being punctured at their ends to afford means for pivotal attachment of said casing, and from the lower end of said casing there being projecting an internally supporting object.-

screw-threaded lug to afford adjustable means for attachment of said casing to a 5 In an air compressor, the combination, comprising, a box-like casing,'cylinders projecting from the upper flanks of said casing in opposite directions, said cylinders being in axial alinement, bearings projecting from the lower flanks of said casing said bearings being in parallel alinement with said cylinders, a twin piston in said cylinders, a shaft rotatably mounted in said bearings and traversing said casing, mechanism for operatively connecting said shaft to'said twin piston, and a conduit connecting the outerends of said cylinders, integrally cylinders.

- 6. In an air compressor, the combination, comprising, a box-like-casing, cylinders projecting from the upper part of the flanks of said casing in opposite directions, said cylinders bein in axial alinement, a twin piston in said cylinders, bearings projectln from the lower partof the flanks of said casing, said bearings being in parallel alinesaid conduit being formed with said casing and said ment with said cylinders, a shaft rotatably,

mounted in said bearings and traversing-said casing, mechanism for operatively connecting said shaft to said twin piston, said mechanlsm comprisin an annular hub, said hub being angularly disposed to the axial line of said shaft, said hu-b bein shaft by a set screw, sai hub having approximately medially a circumferential flange, an annular, cup-shaped shell on said secured to a said /open end of said shell being internally screwthreaded, a follower in said shell in screwthreaded engagement with the open end thereof, annular washers between the outer flank of said annular flange and the bottom of the shell, and between the inner flankof said annular flange and the inner face of said follower, there being notches in the outer face of said follower, means on saidshell and engaging said follower in said notches to prevent rotation of said ifollower, said shell having an arm reaching to, and engaging said twin piston.

In an air compressor, the combination, comprising, a motor, clutch mechanism connecting said motor to the air compressor, a low pressure and a high pressure cylinder said cylinders being axially alined, a twin piston reciprocatively mounted in said cylinders, means for reciprocating said twin piston, manually operated means for initiating the operation of said piston, and automatically actuated means for arresting the operation of said'piston, the latter means including a cylinder head at the end of the high pressure cylinder, 'said cylinder head having a discharge passage leading from said high pressure cylinder, a valve in said discharge during the suction stroke of said high pressure piston, a chamber com risi a two elements, one of said elements eing lntegrally formed with'said cylinder head, there bein in said element a passage connecting said element with said discharge passage, said second element having in its' face an annular depression, said depression having a central through-opening, said second element .havingdownwardly extendin punctured lugs, a diaphragm interposed between said two elements, said'diaphragm being normally in upwardly distended condition, a lever pivotally mounted in said lugs, a follower below said diaphragm, said lever having means passing through said through-opening to act upon said follower to sustain said diaphragm in upwardly distended condition, and means operatively connected to said lever and said clutch mechanism for disconnecting said motor from said air compressor when said diaphragm is downwardly distended by air pressure acting upon said diaphragm.

8. In an air compressor, the combination, of a casing, said casing including two axially alined cylinders, a twin piston in said cylinders, cylinder heads at the outer ends of said cylinders, said casing having laterally extending, axially alined bearings, an operating shaft rotatably mounted in said bearings, a wabbling disk fixed to said operating shaft, said wabbling disk being 015- passage closing said air passage eratively connected to said twin piston, and means for longitudinally adjustin said operating shaft, said operating sha t having externally screw-threaded ends and a hole transversely therethrough, a nut upon each screw-threaded end, the outer face of each nut having radially disposed notches, and pins in said holes and engaging said notches, whereby the position of the twin piston in said cylinders may be adjusted to afford proper clearance between the outer ends of the pistons and said cylinder heads.

9. In an air compressor, the combination, of a motor, clutch mechanism connected to said motor, and an air compressor operatively connected to said clutch mechanism, said air compressor including a low pressure and a high ressure cylinder in axial alinement, a twin piston reciprocatively mounted in said cylinders, means for operating said twin piston, manually operated means for operatively connecting said operating means to said clutch mechanism, and

. automatically operating means for disconnesting said operating means from said clutch mechanism, the latter means incl-uding a rod, one end of said rod being operatively connected to said clutch mechanism, the other end of said rod having a notch, a spiral spring on said rod said spring being tensioned and acting on said rod to move the clutch mechanism out of engagement with said motor, a chamber connected to said high pressure cylinder, a diaphragm in said chamber, a lever ivotally connected to said chamber, one en of said lever being connected to said diaphragm to hold said diaphragm normally in upwardly distended condition, the other end of said lever normally engaging the notch in said rod and holding the clutch mechanism in operative engagement with said motor, said manually operated means including a lever at the end of said rod constructed to move said rod longitudinally to cause engagement of said clutch mechanism with said motor after having been disconnected therewith by said automatically operating mechanism.

In testimony that I claim the foregoing as my invention, 1 have hereunto set my hand.

7 JAMES B. KENDALL. 

